The invention relates to a device which allows a space adjacent to a magnetic source to be protected.
The magnetic energy radiated into a space adjacent to a magnetic source can disrupt the operation of electronic devices (electromagnetic compatibility) and/or present a danger for a human being who occupies this space when this energy results from a high power even over a short duration or from a weaker power to which the human being is, however, exposed over a longer period of time.
Generally, such a device comprises a multilayer shield or screen, such as, for example, that described in document EP1399929. The shield disclosed by this document is wound around an electric cable. It comprises at least two layers of ferromagnetic material.
This method of shielding is not appropriate when the magnetic source has a more complex shape than a simple straight tubular shape. This can be the case when the magnetic source is not limited to the cable itself but also includes connection terminals or various power electronic equipment. This can be the case also for a cable per se when it is subjected to certain bending in static mode in the path from one piece of electrical equipment to another or in dynamic mode when the cables are connected to mobile equipment. This bending can cause rupturing in the layers of ferromagnetic material, which then no longer allows the magnetic field lines to be correctly channeled and which then makes the shield lose the magnetic screen qualities thereof.
To overcome the problems of the prior art, the object of the invention is a device for protecting a space adjacent to a magnetic source against magnetic energy radiated by said source, comprising a first sheet of ferromagnetic material, which sheet is spread between said space and said source. The device is characterized in that it includes a first sheet of diamagnetic or paramagnetic electrically conductive material, which sheet is spread between said first sheet of ferromagnetic material and said space to be protected.
Particularly, the device comprises a second sheet of diamagnetic or paramagnetic electrically conductive material, which sheet is spread between said first sheet of ferromagnetic material and said magnetic source.
More particularly, the device comprises a second sheet of ferromagnetic material, which sheet is spread between said first sheet of ferromagnetic material and said first sheet of electrically conductive material.
Advantageously, said sheet(s) of electrically conductive material has(have) a surface area which is greater than that of the sheet(s) of ferromagnetic material such as to completely cover said sheet(s) of ferromagnetic material.
Preferably, the ferromagnetic material has a relative magnetic permeability with a high value greater than 100000.
In particular, the ferromagnetic material is an iron-based amorphous alloy having a non-orientated nanocrystalline structure.
More particularly, said alloy comprises a chemical element of a group comprising cobalt and nickel.